AMERICANS HAVE barbecue sauce; in the Middle East they have tahini. And in Southeast Asia there is curry paste, aready-made seasoning mixture that is alchemy, transforming whatever bits of meat or grain or vegetable happen to be available into a dish of complexity by just a simple step or two.

Curry paste is not synonymous or always interchangeable with curry powder, which is basically Indian in origin. Curry powder combines various ground dry spices and must be fried gently in ghee or clarified butter to remove the harsh flavor of the raw spices before it is added to other foods. Curry paste, on the other hand, is made from fresh pounded herbs, whole spices and aromatics. It has already been fried to release and then capture the aromatic character of the ingredients and is instantly ready to enhance a variety of foods with its complex and enticing flavors.

Curry pastes are used extensively all over southeast Asia, from Burma through the Indonesian archipelago. Their flavors range from mellow and fragrant to fiery and assertive. The essence of a good curry is not in hot spiciness but in the delicate balance of many varied flavors.

Some of the primary ingredients of curry pastes are shallots, garlic, ginger root, coriander root, lemon grass, chilies, fresh herbs, ground spices and either shrimp paste or fish sauce. The preparation is simple and it can be kept refrigerated for several weeks or frozen indefinitely.

In Asia, a large stone mortar and pestle is used to pound and grind the ingredients. A blender or food processor makes a good substitute if care is taken to mince ginger root, coriander roots and lemon grass before pure'eing with the other ingredients. A heavy rolled steel wok or cast iron dutch oven gives the best heat distribution when cooking the paste, which can be the power behind sauces, bastes, dips, dressings and soups, in addition to curries and stews. It also acts as a seasoning on vegetables, rice and pasta.

A glossary of terms basic to cooking with curry paste:

Coriander roots--Fresh coriander is usually sold with the roots intact. Wash the roots thoroughly to remove sand and cut them off the plants leaving no stem attached. If you have no immediate use for them, they can be tightly wrapped and frozen. No substitute.

Fenugreek--Seed of a tropical plant usually purchased as a pale yellowish powder with a slightly bitter taste. No direct substitute but other ground spices such as allspice, nutmeg, cinnamon or fennel can be used in its place for a slightly different effect.

Fish sauce--Also called nam pla (Thailand), nuoc mam (Vietnam) and petis (Philippines). A dark fishy-tasting liquid essential to curry paste for its saltiness. Its fishy character fades with cooking, leaving a subtle richness. Can be kept indefinitely at room temperature after opening. No substitute.

Lemon grass--A tropical grass with a lemon fragrance available fresh in Asian markets during the spring and summer. Dried lemon grass is a very poor substitute. A better match in flavor would be the zest of 1 lemon without any white pith for each stalk of lemon grass.

Ma grood--(Makrut) Leaves of the Asian wild kafir lime tree. Available fresh in the spring and summer in Thai markets. Dried ma grood leaves are a good substitute and are available year round in Asian markets.

Namprik pla tu--A bottled Thai chili paste containing chili, fish, onion, garlic, sugar and salt. Available in Asian markets. Substitute: namprik payasook, namprik chay dan or bottled Thai chili pastes.

Sambal olek--A convenient bottled mixture of minced chilies, vinegar and salt. Available in Asian markets. Fresh chopped or dried flaked chilies may be substituted in approximately equal proportions. BASIC CURRY PASTE (Makes about 2 cups)

This recipe is only moderately hot. Fresh chilies or sambal olek* can be added to any of the following recipes to taste to increase the incendiary effect. 3 stalks fresh lemon grass, finely minced 2 tablespoons coriander roots, scrubbed and finely minced 3 tablespoons ginger root, finely minced 3 medium onions, chopped 4 cloves garlic, minced 2 tablespoons oil 3 tablespoons oil, for frying 2 teaspoons namprik pla tu* 1 tablespoon sugar 2 tablespoons fish sauce (nam pla*) 2 teaspoons ground fenugreek 4 teaspoons ground coriander 5 ma grood leaves* (optional)

In a food processor or blender combine and pure'e the first 6 ingredients until smooth. Heat the 3 tablespoons of oil over moderate heat in a heavy pan and carefully add the pure'ed mixture. (It splatters if added too fast or the oil is too hot.) Add the remaining ingredients. Continue stirring often to prevent sticking for 15 to 20 minutes. The paste is ready when it has turned a rich brown and the oil has separated from the mixture. Remove the ma grood leaves. If desired correct seasoning by adding more sugar, nam pla (fish sauce) or sambal olek. Cook 1 or 2 minutes more.

To store, cool and spoon into a clean glass container with a tight fitting lid and store in the refrigerator up to 4 weeks. Freeze as you would a liquid. If airtight, curry paste can be kept frozen several months. CURRIED PRAWN AND LEMON GRASS SOUP (6 servings) For the shrimp stock: Reserved shrimp shells 1 stalk lemon grass, chopped Cold water to cover For the soup: 4 cups chicken stock 1 tablespoon curry paste 2 tablespoons fish stock (nam pla)* 1 tablespoon sugar 2 tablespoons tamarind liquid* 1 stalk lemon grass, bruised and tied 3/4 pound shrimp, shelled and deveined (reserve the shells) Juice of 2 lemons

To make the shrimp stock, combine the shrimp shells, the lemon grass and cold water to cover. Bring to a boil and simmer uncovered one-half hour. Strain and discard the shells and lemon grass.

Combine shrimp stock, chicken stock, curry paste, nam pla, sugar and tamarind liquid and the remaining stalk of lemon grass and simmer 5 minutes. Add the shrimp and bring quickly back to a boil, remove from heat immediately, add lemon juice, cover and let stand 5 minutes before serving. GRILLED BABY BACK RIBS IN CURRY PASTE (8 servings) 2 racks of ribs about 2 1/2 pounds each 2 tablespoons wan ja shan soy sauce (paste)* 3 tablespoons medium sherry 2 tablespoons oil 1/2 cup curry paste Iceberg lettuce or napa, shredded for garnish

Separate the racks into individual ribs. Combine remaining ingredients and rub into ribs. Set aside for 1 hour.

Grill over moderately hot charcoal turning often until deep brown and crusty. Serve on a bed of shredded lettuce or napa (cabbage). LOBSTER AND MELON SALAD IN CURRY DRESSING (6 servings) For the sauce: 1/4 cup sour cream 2 tablespoons mayonnaise 3 to 4 tablespoons curry paste Tomalley from the lobster (optional) 3 tablespoons lime juice Zest 1 lime For the salad: Meat from 2 small lobsters, cubed, about 2 1/2 cups 3 cups cantalope balls 2 limes, thinly sliced, zest reserved for garnish 2 cups red onion, julienned lengthwise

Combine the sauce ingredients, stirring to blend well. Stir in the lobster meat and melon balls.

Arrange the lime slices around the rim of a serving plate. Arrange the julienned onions, petal fashion radiating from the center of the plate. Mound the lobster mixture in the center and garnish with the lime zest. SPICY ROAST DUCK, THAI STYLE (4 servings) 4 1/2- to 5-pound duck 1/2 cup curry paste 1/2 cup thick coconut milk 1/2 cup tamarind liquid* Coriander leaves for garnish

With poultry shears remove the backbone of the duck and spread it flat. Lean on the duck to crack the rib and breast bones, being careful not to break the skin. Cut away any obvious pockets of fat.

Combine curry paste, coconut milk and tamarind liquid and rub thoroughly into surface of the duck and allow to marinate 12 to 24 hours.

Prick the duck skin in the fatty areas around the wings and legs. Place the duck, skin side down on a roasting rack and roast at 500 degrees for 1/2 hour.

In the meantime, light a charcoal fire to moderate heat. Remove the duck from the oven and place skin side down on the grill. Cook 15 minutes, taking care not to burn the skin. Turn and cook with the split side down 5 minutes. Turn again and grill another 10 minutes. The flesh should be pinkish and juicy. Remove duck from grill and let it rest a few minutes before serving, garnished with coriander leaves. CURRIED CHICKEN WITH COCONUT MILK (6 servings) 1/2 cup curry paste 2 1/2 cups chicken stock 2 tablespoons fish sauce (nam pla)* 12-ounce can unsweetened coconut milk Sambal olek to taste 1 teaspoon salt 10 to 12 chicken legs, thighs, wings or breasts

Combine the curry paste, chicken stock, nam pla, coconut milk , sambal olek and salt in a dutch oven and heat, stirring to combine. Add the chicken pieces and bring to a boil. Reduce heat, cover and simmer gently for 1 hour. Skim off any fat before serving.

Optional--2 cups of peeled, cubed potatoes can be added 25 minutes before the end of cooking.

This dish benefits from being prepared a day or two in advance to allow the flavors to marry. Reheat gently before serving. Shrimp, fish or vegetables are also excellent cooked in this sauce. CRISP FRIED CURRIED VEGETABLES (6 servings) Oil for stir-frying (about 1 tablespoon) 2 cups carrots, sliced very thinly on the diagonal 1 cup water chestnuts, thinly sliced 2 cups snow peas, trimmed and cut in half diagonally 2 tablespoons curry paste 1 tablespoon rice vinegar 1 tablespoon mirin (sweet Japanese wine) Salt to taste 2 teaspoons mint leaves chopped Mint sprigs for garnish

In a hot wok, heat the oil, add the carrots and stir-fry 2 minutes. Add the water chestnuts and stir 1 minute. Add the snow peas and stir until bright green. Combine the curry paste and the vinegar and mirin and stir into vegetables. Salt to taste and toss in mint leaves. Serve immediately garnished with mint sprigs. *Available in Asian markets